1. Field of Invention
The present invention relates to a patterning method and an integrated circuit structure.
2. Description of Related Art
Non-volatile memories provide the property of multiple entries, retrievals and erasures of data, and are able to retain the stored information even when the electrical power is off. As a result, non-volatile memories are widely used in personal computers and consumer electronic products.
As the level of integration of a non-volatile memory is getting higher, the critical dimension of the same is getting smaller. Minimizing the critical dimension and increasing the level of integration have become the mainstream in the industry, and the key technology is in photolithography.
In the photolithography process, it is known that raising a line or space resolution beyond 65 nm, especially a line/space width of no more than 25/25 nm, in the current state of technology is rather difficult, unless a light source having a shorter wavelength and a corresponding photoresist are used. However, it is very costly to replace existing machines entirely with new machines for this purpose.
Accordingly, how to reduce a line/space width to no more than 25/25 nm with existing machines and processes has become an important topic in the industry.